Integrated circuit with selectable power-on reset mode

Abstract

An integrated circuit (IC) and associated method support using a pre-use configuration for determining an initial/preferred operational mode for the IC from plural operational modes that may be entered following power-up cycles of the IC. The initial/preferred operational mode can be determined after the design phase of the IC so that, during IC operation, wasted power or delay are not incurred by first requiring that the IC power up in a default operational mode and subsequently run executive code to reprogram the IC to enter an operational mode that is preferred for the application for which the IC is being used by the IC integrator/user. The configurations determine clock frequencies and/or power levels for core processing and/or peripheral modules and allow the same IC design/die to be targeted to a spectrum of different power usage/performance applications by the integrator/user.

The invention claimed is: 
     
       1. An integrated circuit (IC), comprising:
 a controller module; and 
 a plurality of component modules, each capable of operating in a plurality of different power modes, wherein the IC is designed to be selectively pre-use configured into any one of a plurality of different selectable power-on reset modes, the power-on reset modes including:
 a first power-on reset mode corresponding to the plurality of component modules operating in a first set of power modes; and 
 a second power-on reset mode corresponding to the plurality of component modules operating in a second set of power modes different from the first set of power modes, such that:
 if the IC is pre-use configured with the first power-on reset mode, then, when the IC is powered up following the pre-use configuration, the controller module causes the component modules to operate directly in the first set of power modes; and 
 if the IC is pre-use configured with the second power-on reset mode, then, when the IC is powered up following pre-use configuration, the controller module causes the component modules to operate directly in the second set of power modes, and 
 
 
 wherein, until the pre-use-configured selected power-on reset mode is changed by programming the IC, the IC boots up in the pre-use configured selected power-on reset mode at each power-on reset of the IC. 
 
     
     
       2. The IC of  claim 1  before being pre-use configured to have a selected power-on reset mode. 
     
     
       3. The IC of  claim 1  after being pre-use configured to have a selected power-on reset mode. 
     
     
       4. The IC of  claim 3 , wherein, after the pre-use-configured IC is powered up the IC can be programmed to change the selected pre-use-configured power-on reset mode to a third power-on reset mode corresponding to the plurality of component modules operating in a third set of power modes, such that, upon a subsequent power-on reset of the IC, the controller causes the component modules to operate in the third set of power modes. 
     
     
       5. The IC of  claim 1 , wherein if the IC is pre-use configured with a power-on reset mode, then, when the IC is powered up following the pre-use configuration, it will subsequently selectively shut down portions of the controller module to save power. 
     
     
       6. The IC of  claim 1 , wherein:
 the first set of power modes comprises a first set of voltage levels and clock characteristics for the plurality of component modules; and 
 the second set of power modes comprises a second set of voltage levels and clock characteristics for the plurality of component modules, wherein at least one of a voltage level and a clock characteristic of the second set of power modes is different from at least one of a corresponding voltage level and a corresponding clock characteristic of the first set of power modes. 
 
     
     
       7. The IC of  claim 6 , wherein the clock characteristics comprise at least one of clock frequency and a clock gating. 
     
     
       8. The IC of  claim 1 , wherein the IC is pre-use configurable by selectively configuring hardware within the IC. 
     
     
       9. The IC of  claim 1 , wherein the IC is pre-use configurable by selectively burning one or more fuses within the IC. 
     
     
       10. The IC of  claim 1 , wherein the IC is pre-use configurable by selectively configuring non-volatile memory of the IC. 
     
     
       11. The IC of  claim 1 , wherein the IC is pre-use configurable by selectively configuring external wiring to the IC.